US2032133A - Disazo dyestuff and its production - Google Patents

Description

Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE DISAZO DYESTUFF AND ITS PRODUCTION Adolf Krebser, Basel, Switzerland, assignor to the firm J. R. Geigy A. G., Basel, Switzerland No Drawing. Application March 20, 1935, Serial No. 12,108. In Germany April 12, 1934 2 Claims. (Cl. 26077) This invention relates to the manufacture of prising; there is nothing in literature or in techdisazo dyestufis by coupling a tetrazotized dinical knowledge which would lead one to suppose amino base according to the following general that the difference might exist. formula: The following example illustrates the inven- H2NR,SR NH2 tion: 5

21.6 kilos of thio-aniline (4,4'-diamino-diwherein R is an aromatic residue, with a para phenyl-sulphide) are tetrazotized in the usual substituted phenol capable of being coupled and manner and the product is coupled in solution containing no sulphonic or carboxylic group, so alkaline with sodium carbonate with 21.6 kilos as to form a disazo dyestuff. The new dyestuifs of 4-hydroxy-1-methylbenzene. The yellow-orthus obtained are very suitable for dyeing celluange powder thus produced dissolves in concenlose ester lacquers, spirit lacquers, oils and fats trated sulphuric acid to a brown-red solution w and also for use in the graphic arts, for instance, and dyes mixtures of nitro-cellulose and acetylcopper-block printing. cellulose and the mixtures of resins and solvents The U. S. Patent No. 1,819,957 discloses the use used in copper-block printing pure yellow tints. of similar dyestuffs from diamino bases of the di- The solubility in these mixtures is remarkable; or tri-arylmethane series and amines and phethe depth of color is nearly double that of the nols capable of being coupled for dyeing fats already known dyestuifs, for example, those of and oils. As compared with the older dyestuffs U. S. Patent No. 1,819,957. for fats these dyestufis are distinguished by the What I claim is:-- fac tha t y have new Properties ch, for 1. A process for the manufacture of a disazo th fi s m ma s it possible t use y s s dyestufi, insoluble in water, consisting in couof this kind for graphic purposes, for example, in pling tetr-azotized thio-aniline with 4-hydroxyproducing two-tone colors in copper-block printl-methylbenzene.

ing. 2. Disazo dyestuff, insoluble in water, of the 5 When, however, in accordance with the present following formula,

invention, the -CH2 or CHR group in the diamino base of the aforesaid patent is replaced N=N- s-C -N=N by sulphur as mono-atomic link member for uniting the two aromatic bases, there are ob- 0H OH tained by tetrazotizing and coupling with parasubstituted phenols disazo dyestuffs insoluble in CH: CH

water which are distinguished by very good solubility in the solvents and varnish mixtures used said dyestufi having a great coloring power and in the graphic art and are differentiated from a good fastness to light and being suitable for the known dyestufis by a much better fastness dyeing cellulose ester lacquers, spirit lacquers, to light and by a considerably greater coloring oils and fats and also for use in the graphic arts. power. This diiference in coloring power is sur- ADOLF KREBSER.